Pump speed command generation algorithm for magnetorheological power steering coupling

Abstract

A method for determining a speed of a power steering pump used in a power steering assembly of a vehicle that has particular application in a vehicle using a magneto-rheological hydraulic power steering (MRHPS) system for improving the fuel efficiency and ride comfort of the vehicle, and for reliable functioning of the power steering system. The method includes determining an angle of rotation of the steering wheel and a rate of change of the angle of rotation of the steering wheel based on the angle of rotation of the steering wheel of the vehicle. The method further includes determining the speed of the vehicle and the speed of the power steering pump based on the angle of rotation of the steering wheel, the rate of change of the angle of rotation of the steering wheel and the speed of the vehicle.

What is claimed is: 
     
       1. A method for determining a speed of a power steering pump used in a power steering assembly of a vehicle, wherein the power steering pump drives a steering gear of the power steering assembly based on an input given to a steering wheel of the vehicle, said method comprising:
 using a sensor to determine an angle of rotation of the steering wheel; 
 using a controller to determine a rate of change of the angle of rotation of the steering wheel based on the angle of rotation of the steering wheel; 
 using a sensor to determine a speed of the vehicle; and 
 using the controller to determine the speed of the power steering pump, wherein the speed of the power steering pump is determined based on the angle of rotation of the steering wheel, the rate of change of the angle of rotation of the steering wheel and the speed of the vehicle. 
 
     
     
       2. The method according to  claim 1  wherein the speed of the power steering pump is determined using a plurality of arranged sets of data, wherein each of the plurality of arranged sets of data is a representation of a set of values of speed of the power steering pump corresponding to a set of values of the angle of rotation of the steering wheel and the rate of change of the angle of rotation of the steering wheel. 
     
     
       3. The method according to  claim 2  wherein each of the plurality of arranged sets of data corresponds to a predetermined range of the speed of the vehicle. 
     
     
       4. The method according to  claim 2  wherein at least one of the plurality of arranged sets of data is a table. 
     
     
       5. The method according to  claim 2  wherein at least one of the plurality of arranged sets of data is provided by analytical functions. 
     
     
       6. The method according to  claim 1  wherein the speed of the power steering pump at zero value of the speed of the vehicle is determined using an arranged set of data, wherein the arranged set of data is a representation of a set of values of speed of the power steering pump corresponding to a set of values of the angle of rotation of the steering wheel and the rate of change of the angle of rotation of the steering wheel, wherein the arranged set of data corresponds to the zero value of the speed of the vehicle. 
     
     
       7. The method according to the  claim 6  wherein the value of the speed of the power steering pump at a non-zero value of the vehicle speed is determined based on the speed of the power steering pump at the zero value of the speed of the vehicle and a correction factor. 
     
     
       8. The method according to  claim 6  wherein the arranged set of data is a table. 
     
     
       9. The method according to  claim 6  wherein the arranged set of data is provided by analytical functions. 
     
     
       10. The method according to  claim 1  further comprises determining the speed of the power steering pump based on a temperature of a coil of a magneto-rheological clutch. 
     
     
       11. The method according to  claim 1  further comprises determining the speed of the power steering pump based on a speed of an engine of the vehicle. 
     
     
       12. The method according to  claim 1  further comprises changing the speed of the power steering pump using a feedback control. 
     
     
       13. The method according to  claim 1  further comprises determining a maximum speed of the power steering pump and maintaining the speed of the power steering pump below the maximum speed of the power steering pump. 
     
     
       14. A method for determining an optimum speed of a power steering pump used in a magneto-rheological hydraulic power steering (MRHPS) system of a vehicle, wherein the power steering pump drives a steering gear used in the MRHPS system based on an input given to a steering wheel of the vehicle, said method comprising:
 using a sensor to determine an angle of rotation of the steering wheel; 
 using a controller to determine a rate of change of the angle of rotation of the steering wheel based on the angle of rotation of the steering wheel; 
 using a sensor to determine a speed of the vehicle; and 
 using the controller to determine the speed of the power steering pump, wherein the speed of the power steering pump is determined using one or more arranged sets of data, wherein each of the one or more arranged sets of data is a representation of a set of values of speed of the power steering pump corresponding to a set of values of the angle of rotation of the steering wheel and the rate of change of the angle of rotation of the steering wheel, wherein each of the one or more sets of data corresponds to a predetermined range of the speed of the vehicle. 
 
     
     
       15. The method according to  claim 14  further comprises determining the speed of the power steering pump based on a speed of an engine of the vehicle and a temperature of a coil of a magneto-rheological clutch.